Boiler Hookup circulators

[freeacs]

Hello, I have a boiler that heats and does water for my whole house. Radiant heat, super store on the water tank. I have circulators on every radiant zone, which seems fine. My question is that there is one circulator that comes off the supply of the boiler and feeds the "loop" that passes by each zone and then returns to the boiler. It is my understanding that the zones turn on when they call for heat and draw from the "loop" but that the circulator on the loop is always on heating the loop to 180 degrees. I have seen other boilers that don't have a circulator on the supply pipe and don't have a "loop". It seems inefficient to me to have this always on and heating even if no zones are asking for hot water, and this seems validated by the fact that the room for the furnace is very warm all the time (great for drying mittens). I am thinking of getting this circulator wired so that it only turns on if one of the others turn on. Any thoughts from anyone? TIA, ACS

[Phil Again]

Quick question:

Let us presume you have 4 room zones, plus one for the potable hot water tank, for a total of 5. Do all 5 zones have check valves for one way hot water flow?

Pretend that one room zone is in the attic, and has a much lower R-factor insulation than the other 3 room zones. This thermostat will request hot water more than the others. In some installations, without check valves, when only one pump turns on, the output manifold of the boiler(s) that feeds all 5 pumps will draw hot water from all connections on the manifold. In short, one pump turns on, and the other zones are going to have reverse flow (complex relationship to determine the percentage each off-line pump feeds the flow to the on-line pump.)

If you have check valves on each zone leg off the manifold, then reverse flow won't occur. And the return copper line from each off-line zone should be cool, (not hot!)

There-fore, please post back if you have check valves on each room zone plus the potable hot water tank zone.

[RBM]

That's a primary loop. Often that circulator is controlled by an outdoor temperature sensor working through a controller like Tekmar to determine the optimal temperature for the system

[freeacs]

Well, I don't know if there are check valves as I am not a plumber. I will check if the return is cool from each return. I would think not having check valves (and having reverse flow) would be quite bad, is this common? Is it a good/bad idea? Would a check valve make a difference in how things should perform? ACS

[Edwin Pawlowski]

Not a check valve, but they do have a flow valve that acts as one. This is one of a few b rands that will work. They can be opened in case of circulator failure for gravity flow.

That is called sloppy design and installation.

[Phil Again]

I don't know about outdoor sensor controlling a circulator.

I don't know how common not having a flow valve (check valve?) is. The system I lived with didn't have them. Yes, it was not a good idea not having them. I was told expensive (Labor cost mostly) and they fail. Experts can comment on that statement.

What I was thinking, and it is only my thinking, a zone circulator pump will draw hot water from the manifold. The pump will draw from the manifold the least resistance source of hot water. If there is a primary loop with a pump, wouldn't the source of least resistance flow of hot water be from the boiler? Thus the reverse flow should be minimized, yes? But then again, maybe even in this plan, a reverse flow inhibitor might still be needed.

[beecrofter]

INSULATE THE PIPING IN EITHER CASE

[noname87]

Are you sure that each loop has a circulator and not a zone control valve?

[RBM]

On any hydronic system there is either going to be flow checks or zone valves to prevent reverse flow. Today, you can get the flow check built into the circulator

[freeacs]

I am pretty sure it is a circulator, they are all the same green things with electronic connections. I don't know if these are "zone control valves" as I don't know what that is. I have insulated all the pipes (though not that well as there are so many connections it is hard to get the insulation around enough). I have asked my electrician to check out how he has it hooked up. I guess I will ask the plumber to tell me how things are hooked up as well and if there would be any reverse flow. Thank you all for your comments. ACS

[Edwin Pawlowski]

Mine are trouble free for 30 years. Cost? Almost nothing in labor as it is a simple sweat joint or threaded joint, nothing complex at all.

[Edwin Pawlowski]

Maybe. That heat loss is not lost, it goes into the house that you are trying to heat anyway. If there is an area you don't want to heat insulation helps.

[noname87]